Pt对镍基单晶高温合金持久性能的影响

INFLUENCE OF Pt ON THE CREEP RUPTURE PROPERTIES OF Ni-BASED SINGLE CRYSTAL SUPERALLOY

研究了不同Pt含量的镍基单晶高温合金在1100℃,180 MPa和1000℃,310 MPa条件下的持久性能,采用SEM和TEM等方法分析了Pt对合金持久变形组织和位错形态的影响.结果表明,Pt略微降低了合金在1100℃,180 MPa条件下的持久寿命,较大降低了合金在1000℃,310 MPa条件下的持久寿命.不同Pt含量的合金在不同条件的持久断裂均表现为塑性断裂,断口附近可以观察到大量的微孔洞和微裂纹.不同Pt含量合金持久变形后均在g/g'界面上形成致密的位错网.Pt对合金持久性能影响的主要原因在于Pt促进了TCP相的形成,而TCP相与基体界面吸收大量变形过程中产生的空位而导致孔洞形核,随着变形的继续孔洞成为裂纹源.

The Ni- based single crystal superalloys are considered to be the major materials for advanced areo- engine blades. In order to improve the high temperature properties of Ni- based single crystal superalloys,many refractory elements are introduced into this kind of alloys. Recently Pt has been suggested to be the alloying elements of advanced Ni-based single crystal superalloys. However, there are no researches for the effects of Pt on creep rupture properties of advanced single crystal superalloys. In this work, the influence of Pt element on the creep rupture properties of a Re-containing single crystal superalloy was investigated. The high-temperature creep rupture properties of the Pt-containing Ni-based single crystal superalloy at 1100 ℃, 180 MPa and 1000 ℃, 310 MPa were investigated. The deformation microstructure and the morphology of dislocations were studied by SEM and TEM.The results show that the creep rupture life of Pt-containing superalloy decrease slightly at 1100 ℃, 180 MPa and decreased obviously at 1000 ℃, 310 MPa. The fracture models of different alloys are all ductile fracture, and many irregular microviods and microcracks can be observed in the fracture surfaces. After high temperature creep deformation, regular dislocation networks formed at the g/g’ interfaces. The differences of creep rupture properties among those alloys are that Pt element may promote the formation of TCP phase, and the interface between the TCP phase and g matrix may be favorite sites of the initiation of microvoids and microcracks.